Outdoor unit of air conditioner

ABSTRACT

An outdoor unit includes: two fan motors that respectively drive two outdoor fans arranged one above the other; a controller including a fan motor power supply capable of separately supplying power to each of the two fan motors connected to two fan motor connectors; and an electrical component temperature sensor that measures temperatures of electrical components. The controller includes a control circuitry that detects which of the two fan motor connectors each of the two fan motors is connected to and supplies power in such a way as to drive the upper one of the outdoor fans based on a result of the detection at the time of single-fan operation. The detection is performed based on comparison between temperatures of the electrical components at the start of the single-fan operation and temperatures of the electrical components after a set time has elapsed since the start of the single-fan operation.

CROSS REFERENCE TO RELATED APPLICATION

This application is a U.S. national stage application of International Patent Application No. PCT/JP2018/032754 filed on Sep. 4, 2018, the disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an outdoor unit of an air conditioner that sends outside air to an outdoor heat exchanger with a fan and performs heat exchange between a refrigerant and the outside air.

BACKGROUND

Suppose that in an air conditioner, two outdoor fans that send outside air to an outdoor heat exchanger are installed on an outdoor unit such that the two outdoor fans are arranged one above the other. In the case where the air conditioner performs cooling operation when the temperature of the outside air is low, the amount of heat exchange between the outside air and a refrigerant in the outdoor heat exchanger reaches or exceeds operating capacity required for an indoor unit, so that the inside of a room is excessively cooled.

There is a technique for preventing heat exchange from exceeding the operating capacity required for the indoor unit in such a case, by stopping the lower outdoor fan and rotating only the upper outdoor fan to reduce the amount of heat exchange between the outside air and the refrigerant in the outdoor heat exchanger. In this technique, the upper outdoor fan is rotated. Therefore, outside air does not stay in the vicinity of electrical components including an outside air temperature sensor provided in the upper part of a machine chamber, so that the accuracy of a value to be detected by the outside air temperature sensor and cooling efficiency of the electrical components are maintained.

Meanwhile, a wire for supplying drive electric power to a fan motor that rotates each of the two outdoor fans may be connected to the wrong fan motor at the time of, for example, assembling in a factory or replacement of the fan motor during maintenance work. In this case, the lower fan located away from the outside air temperature sensor and the electrical components will rotate. Therefore, the temperature of outside air cannot be accurately detected, and in addition, the electrical components cannot be cooled. Thus, there is a possibility that the electrical components are overheated and break down.

Patent Literature 1 proposes a method for rotating an intended fan motor by providing a mode for determining the connection states of two fan motors based on a value detected by an outside air temperature sensor, detecting an increase in the temperature of an outdoor heat exchanger based on an increase in the value detected by the outside air temperature sensor, and switching destinations of drive electric power supply in the case where it is determined that connections of the two fan motors have been reversed.

Patent Literature

Patent Literature 1: Japanese Patent No. 5516466

However, there is a possibility that the method disclosed in Patent Literature 1 does not enable improper connection to be detected in the case of an outdoor unit of a multi air conditioning system for buildings, capable of being connected to a plurality of indoor units and separately operating or stopping each indoor unit. The multi air conditioning system for buildings is also referred to as a variable refrigerant flow (VRF) system. In the VRF system, an outdoor unit is generally selected which has a heat exchange capacity sufficient to allow all the connected indoor units to operate. In the multi air conditioning system for buildings, when only a small number of indoor units are operated for cooling, an outdoor heat exchanger will have a sufficient heat exchange capacity with respect to the operating capacity required for the indoor units. Therefore, the temperature of the outdoor heat exchanger hardly increases and the value detected by the outside air temperature sensor does not increase either, so that improper connection cannot be detected.

As described above, there has been a problem that improper connections of fan motors may not be detected in the method for detecting improper connections of fan motors based on a value detected by an outside air temperature sensor.

SUMMARY

The present invention has been made in view of the above, and an object of the present invention is to obtain an outdoor unit of an air conditioner capable of improving the probability of detecting improper connections of fan motors.

To solve the above problems and achieve the object an outdoor unit of an air conditioner according to the present invention includes: a refrigerant circuit including a compressor, a flow path switch, an outdoor heat exchanger, a decompressor, and indoor heat exchangers connected via refrigerant pipes; two outdoor fans to supply air to the outdoor heat exchanger, the two outdoor fans being arranged one above the other; two fan motors to drive the respective two outdoor fans; a controller including two fan motor connectors and a fan motor power supply, the two fan motor connectors being capable of being connected to the fan motors, the fan motor power supply being capable of separately supplying power to each of the two fan motors connected to the fan motor connectors; and electrical component temperature sensors to measure temperatures of electrical components including at least components included in the controller, the electrical component temperature sensors being installed in an electrical component box in which the controller is enclosed. The controller includes a control circuitry, wherein at a time of single-fan operation in which only upper one of the two outdoor fans is operated, the control circuitry is configured: to detect each of the two fan motors is connected to which of the two fan motor connectors; and to supply power in such a way to drive upper one of the outdoor fans based on a result of the detection, wherein the detection is performed based on comparison between temperatures of the electrical components at a start of the single-fan operation and temperatures of the electrical components after a set time has elapsed since the start of the single-fan operation.

An outdoor unit of an air conditioner according to the present invention has an effect of enabling the probability of detecting improper connections of fan motors to be improved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a refrigerant circulation path of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the inside of an outdoor unit of the air conditioner according to the first embodiment.

FIG. 3 is a block diagram of a control system of the outdoor unit of the air conditioner according to the first embodiment.

FIG. 4 is a flowchart illustrating an operation flow of single-fan operation of the outdoor unit of the air conditioner according to the first embodiment.

FIG. 5 is a block diagram of a control system of an outdoor unit of an air conditioner according to a second embodiment of the present invention.

FIG. 6 is a flowchart illustrating an operation flow of single-fan operation of the outdoor unit of the air conditioner according to the second embodiment.

FIG. 7 is a diagram illustrating a configuration in which the function of a control circuitry of the outdoor unit of the air conditioner according to the first embodiment or the second embodiment is implemented by hardware.

FIG. 8 is a diagram illustrating a configuration in which the function of the control circuitry of the outdoor unit of the air conditioner according to the first embodiment or the second embodiment is implemented by software.

DETAILED DESCRIPTION

Outdoor units of air conditioners according to embodiments of the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

First Embodiment

FIG. 1 is a diagram illustrating a refrigerant circulation path of an air conditioner according to a first embodiment of the present invention. In an air conditioner 100 according to the first embodiment, a plurality of indoor units 80 a and 80 b is connected to an outdoor unit 90 to form a VRF system.

The outdoor unit 90 includes a compressor 1, a flow path switch 3, an outdoor heat exchanger 4, a first stationary valve 5, and a second stationary valve 6. The compressor 1, the flow path switch 3, the outdoor heat exchanger 4, the first stationary valve 5, and the second stationary valve 6 are connected by refrigerant pipes to form a refrigerant circuit 30. The compressor 1 sucks a refrigerant, compresses the sucked refrigerant to put the refrigerant into a high-temperature and high-pressure state, and conveys the refrigerant to the refrigerant circuit 30. The flow path switch 3 is provided on the downstream side of the compressor 1, and switches between the flow of the refrigerant for heating operation and the flow of the refrigerant for cooling operation. The outdoor heat exchanger 4 performs heat exchange between air and the refrigerant. The outdoor heat exchanger 4 acts as a condenser during the cooling operation and as an evaporator during the heating operation.

Furthermore, the outdoor unit 90 includes: various sensors, such as pressure sensors and temperature sensors; and a controller 16 including a substrate and a control circuitry 19. The controller 16 is electrically connected to the various sensors and the flow path switch 3. Examples of the sensors included in the outdoor unit 90 include an outside air temperature sensor 9, an electrical component temperature sensor 17, a high-pressure side pressure sensor 2, and a low-pressure side pressure sensor 14. The outside air temperature sensor 9 detects the temperature of outside air. The electrical component temperature sensor 17 detects the temperature of the substrate of the controller 16. Furthermore, the high-pressure side pressure sensor 2 is provided on the discharge side of the compressor 1, and detects the high-pressure side pressure of the refrigerant. The high-pressure side pressure of the refrigerant is also referred to as condenser pressure. Furthermore, the low-pressure side pressure sensor 14 is provided on the intake side of the compressor 1, and detects the low-pressure side pressure of the refrigerant. The low-pressure side pressure of the refrigerant is also referred to as evaporator pressure.

Furthermore, the outdoor unit 90 includes outdoor fans 7 a and 7 b and fan motors 8 a and 8 b. The outdoor fans 7 a and 7 b supply air to the outdoor heat exchanger 4. The fan motors 8 a and 8 b drive the outdoor fans 7 a and 7 b, respectively. A propeller fan can be applied to the outdoor fans 7 a and 7 b. FIG. 2 is a perspective view of the inside of the outdoor unit of the air conditioner according to the first embodiment. As illustrated in FIG. 2, the fan motors 8 a and 8 b are fixed to a fan motor mounting part 50. FIG. 3 is a block diagram of a control system of the outdoor unit of the air conditioner according to the first embodiment. As illustrated in FIG. 3, the fan motors 8 a and 8 b are driven by the control circuitry 19 included in the controller 16 via a fan motor power supply 20, fan motor connectors 15 a and 15 b, and fan motor wirings 18 a and 18 b. The outdoor fans 7 a and 7 b blow air into the controller 16 to cool the substrate. As illustrated in FIG. 2, the controller 16 is enclosed in an electrical component box 40. The electrical component box 40 is attached to the upper part of a separator 51. Electrical components to be housed in the electrical component box 40 include at least components that constitute the controller 16. The components included in the controller 16 are exemplified by a terminal block for connection to a power source, and various sensors as well as a circuit board and electronic components. Furthermore, slits (not illustrated) are provided in the separator 51. The slits enable the controller 16 to be cooled with air blown by the outdoor fans 7 a and 7 b.

The indoor units 80 a and 80 b include decompressors 10 a and 10 b and indoor heat exchangers 11 a and 11 b, respectively. The decompressors 10 a and 10 b decompress and expand the refrigerant. The decompressors 10 a and 10 b are connected to the indoor heat exchangers 11 a and 11 b, respectively, by refrigerant pipes. The indoor heat exchangers 11 a and 11 b perform heat exchange between air blown by a fan (not illustrated) and the refrigerant. The indoor heat exchangers 11 a and 11 b act as evaporators during the cooling operation and as condensers during the heating operation. An expansion valve can be applied to the decompressors 10 a and 10 b.

Furthermore, the indoor units 80 a and 80 b include various temperature sensors. The various sensors of the indoor units 80 a and 80 b and the decompressors 10 a and 10 b are electrically connected to the controller 16 similarly to the various sensors of the outdoor unit 90. The temperature sensors of the indoor units 80 a and 80 b can be exemplified by evaporator temperature sensors that detect the evaporator temperatures of the indoor heat exchangers 11 a and 11 b. As illustrated in FIG. 1, the evaporator temperature sensors include indoor liquid pipe temperature sensors 12 a and 12 b provided on liquid pipes and indoor gas pipe temperature sensors 13 a and 13 b provided on gas pipes.

As illustrated in FIG. 1, the air conditioner 100 includes a plurality of the indoor units 80 a and 80 b. The indoor units 80 a and 80 b are connected in parallel between the first stationary valve 5 and the second stationary valve 6 by refrigerant pipes. The indoor heat exchanger 11 a and the decompressor 10 a are connected in the indoor unit 80 a. The indoor heat exchanger 11 b and the decompressor 10 b are connected in the indoor unit 80 b. The indoor heat exchanger 11 a is provided with the indoor liquid pipe temperature sensor 12 a and the indoor gas pipe temperature sensor 13 a. The indoor heat exchanger 11 b is provided with the indoor liquid pipe temperature sensor 12 b and the indoor gas pipe temperature sensor 13 b.

The compressor 1, the flow path switch 3, the outdoor heat exchanger 4, the first stationary valve 5, the decompressors 10 a and 10 b, the indoor heat exchangers 11 a and 11 b, and the second stationary valve 6 are connected in sequence by pipes to form the refrigerant circuit 30 that circulates the refrigerant.

The controller 16 controls operation of the refrigerant circuit 30 and the outdoor fans 7 a and 7 b. Specifically, based on values detected by the various sensors, the controller 16 controls: the capacity of the compressor 1; the opening degrees of the decompressors 10 a and 10 b; and the driving of the outdoor fans 7 a and 7 b.

Among the various sensors included in the outdoor unit 90, the outside air temperature sensor 9 is attached above the outdoor heat exchanger 4. Therefore, the outside air temperature sensor 9 is easily affected by the state of outside air in the vicinity of the outdoor heat exchanger 4. When only one of the indoor units 80 a and 80 b is operated, the outdoor heat exchanger 4 has a sufficient heat exchange capacity with respect to the operating capacity required for the indoor unit 80 a or the indoor unit 80 b. Therefore, the temperature of the outdoor heat exchanger 4 hardly rises, and a value detected by the outside air temperature sensor 9 does not rise either. Furthermore, when it is windy outside, the flow of outside air to the outdoor heat exchanger 4 is caused without the use of the rotation of the outdoor fans 7 a and 7 b. Thus, the outside air does not stay, and the value detected by the outside air temperature sensor 9 does not rise. Furthermore, since the outdoor heat exchanger 4 acts as an evaporator during the heating operation, the temperature of the refrigerant decreases and the value detected by the outside air temperature sensor 9 also decreases.

Meanwhile, the following can be said about the electrical component temperature sensor 17 among the various sensors included in the outdoor unit 90. A value detected by the electrical component temperature sensor 17 rises even when only one of the indoor units 80 a and 80 b is operated. This is because heat generation in the electrical components is always caused by current flowing through the electrical components and the resistance values of the electrical components. Furthermore, even when it is windy outside, a rise in electrical component temperature can be detected without being affected by the outside wind. This is because the electrical component temperature sensor 17 is installed in the electrical component box 40. The electrical component temperature sensor 17 is installed in the electrical component box 40, and is shielded from the outdoor fans 7 a and 7 b except for the slit portion provided in the separator 51. Therefore, the result of measurement measured by the electrical component temperature sensor 17 is less likely to be affected by airflow generated by the outdoor fans 7 a and 7 b than the result of measurement measured by the outside air temperature sensor 9. Furthermore, heat generation in the electrical components is always caused by the current flowing through the electrical components and the resistance values of the electrical components even during the heating operation, so that a rise in electrical component temperature can be detected.

FIG. 4 is a flowchart illustrating an operation flow of single-fan operation of the outdoor unit of the air conditioner according to the first embodiment. In step S101, the control circuitry 19 determines whether a single-fan operation start condition is satisfied. If the single-fan operation start condition is satisfied, a determination of “Yes” is made in step S101, and the process proceeds to step S102. If the single-fan operation start condition is not satisfied, a determination of “No” is made in step S101, and step S101 is repeated.

In step S102, the control circuitry 19 outputs, to the fan motor power supply 20, a command to supply power only to the fan motor 8 a, which is the upper fan motor, and stop supply of power to the fan motor 8 b, which is the lower fan motor. Furthermore, the control circuitry 19 stores the temperatures of the electrical components measured by the electrical component temperature sensor 17. In this way, the control circuitry 19 performs the single-fan operation.

In step S103, the control circuitry 19 determines whether a set time has elapsed since the single-fan operation was started. If the set time has elapsed since the single-fan operation was started, a determination of “Yes” is made in step S103, and the process proceeds to step S104. If the set time has not elapsed, a determination of “No” is made in step S103, and step S103 is repeated.

In step S104, the control circuitry 19 determines whether differences between the current values of the temperatures of the electrical components measured by the electrical component temperature sensor 17 and the temperatures of the electrical components at the start of the single-fan operation are less than a threshold value. If the differences between the temperatures of the electrical components at the start of the single-fan operation and the current temperatures of the electrical components are less than the threshold value, a determination of “Yes” is made in step S104, and the process proceeds to step S105. If the differences between the temperatures of the electrical components at the start of the single-fan operation and the current temperatures of the electrical components are equal to or greater than the threshold value, a determination of “No” is made in step S104, and the process proceeds to step S106.

In step S105, the control circuitry 19 determines that connections of the outdoor fans 7 a and 7 b are normal, and the process proceeds to step S108.

In step S106, the control circuitry 19 determines that the connections of the outdoor fans 7 a and 7 b have been reversed, and the process proceeds to step S107. In step S107, the control circuitry 19 stops supply of power to the fan motor connector 15 a, and starts supply of power to the fan motor connector 15 b. That is, the control circuitry 19 switches power supply for the fan motor connectors 15 a and 15 b. Therefore, supply of power to the fan motor 8 b connected to the fan motor connector 15 a in a manner opposite to a normal state is stopped, and supply of power to the fan motor 8 a connected to the fan motor connector 15 b is started. When step S107 is completed, the process proceeds to step S108.

In step S108, the controlcircuitry 19 determines whether a single-fan operation end condition is satisfied. If the single-fan operation end condition is satisfied, a determination of “Yes” is made in step S108, and the process ends. If the single-fan operation end condition is not satisfied, a determination of “No” is made in step S108, and step S108 is repeated.

The outdoor unit 90 of the air conditioner 100 according to the first embodiment detects improper connections of the fan motors 8 a and 8 b based on the values detected by the electrical component temperature sensor 17. Therefore, improper connections of the fan motors 8 a and 8 b can be detected even when the cooling operation is performed by only a small number of the indoor units, that is, the cooling operation is performed by only one of the indoor units 80 a and 80 b.

Furthermore, in the outdoor unit 90 of the air conditioner 100 according to the first embodiment, the electrical component temperature sensor 17 is installed in the electrical component box 40. Thus, improper connections of the fan motors 8 a and 8 b can be detected even under the condition that the value detected by the outside air temperature sensor 9 does not rise since it is windy outside and air is not stagnant around the outside air temperature sensor 9.

Note that the amount of heat exchange between the outside air and the refrigerant in the outdoor heat exchanger may also reach or exceed the operating capacity required for the indoor units during the heating operation in an environment with high outside air temperature as well as the above-described cooling operation in an environment with low outside air temperature. In this case, even if only the upper one of the outdoor fans 7 a and 7 b is rotated so as to reduce the amount of heat exchange between the outside air and the refrigerant and secure the operating capacity required in the indoor units 80 a and 80 b, the temperature of the outside air measured by the outside air temperature sensor 9 decreases. This is because the outdoor heat exchanger 4 acts as an evaporator during the heating operation. Therefore, improper connection cannot be detected during the heating operation by use of the method for detecting improper connection based on an increase in the value detected by the outside air temperature sensor 9. However, the outdoor unit 90 of the air conditioner 100 according to the first embodiment detects improper connections of the fan motors 8 a and 8 b based on the values detected by the electrical component temperature sensor 17. Thus, the improper connections of the fan motors 8 a and 8 b can be detected even in the case where the heating operation is performed in the environment with high outside air temperature.

Second Embodiment

FIG. 5 is a block diagram of a control system of an outdoor unit of an air conditioner according to a second embodiment of the present invention. The outdoor unit 90 of the air conditioner 100 according to the second embodiment is different from the outdoor unit 90 of the air conditioner 100 according to the first embodiment in that the controller 16 includes a connection state memory 21. The connection state memory 21 stores connection state information indicating which of the fan motor connectors 15 a and 15 b each of the fan motors 8 a and 8 b is connected to.

FIG. 6 is a flowchart illustrating an operation flow of single-fan operation of the outdoor unit of the air conditioner according to the second embodiment. This operation flow differs from the operation flow of the single-fan operation of the outdoor unit 90 according to the first embodiment in that the processes of steps S109 and S110 have been added between steps S101 and S102.

When the single-fan operation start condition is satisfied, the control circuitry 19 determines, in step S109, whether the connection state information is stored in the connection state memory 21. If the connection state information is stored in the connection state memory 21, a determination of “Yes” is made in step S109, and the process proceeds to step S110. In step S110, the connection state information is read out from the connection state memory 21, and the process proceeds to step S102. If the connection state information is not stored, a determination of “No” is made in step S109, and the process proceeds to step S102.

In step S102, the control circuitry 19 outputs, to the fan motor power supply 20, a command to supply power only to the fan motor 8 a, which is the upper fan motor, and to stop supply of power to the fan motor 8 b, which is the lower fan motor. At this time, in the case where the connection state information has been read in step S110, power is supplied to one of the fan motor connectors 15 a and 15 b, connected to the fan motor 8 a so that power is supplied to the fan motor 8 a.

Subsequent operation is the same as the operation of the outdoor unit according to the first embodiment, except that the connection state information is stored in the connection state memory 21 in step S105 or step S106.

The outdoor unit 90 of the air conditioner 100 according to the second embodiment can start the single-fan operation so that only the outdoor fan 7 a is driven in the case where the connection state information is stored in the connection state memory 21. Therefore, the cooling of the controller 16 can be started immediately after the start of the single-fan operation, and it is thus possible to reduce the possibility that the electrical components may break down due to an increase in temperature.

The function of the control circuitry 19 of the outdoor unit 90 of the air conditioner 100 according to the first embodiment or second embodiment described above is implemented by processing circuitry. The processing circuitry may be dedicated hardware, or may be a processing device that executes a program stored in a storage device.

In the case where the processing circuitry is dedicated hardware, the processing circuitry corresponds to a single circuit, a composite circuit, a programmed processor, a parallel-programmed processor, an application specific integrated circuit, a field programmable gate array, or a combination thereof. FIG. 7 is a diagram illustrating a configuration in which the function of the control circuitry of the outdoor unit of the air conditioner according to the first embodiment or the second embodiment is implemented by hardware. A logic circuit 29 a that implements the function of the control circuitry 19 is incorporated in processing circuitry 29.

In the case where the processing circuitry 29 is a processing device, the function of the control circuitry 19 is implemented by software, firmware, or a combination of software and firmware.

FIG. 8 is a diagram illustrating a configuration in which the function of the control circuitry of the outdoor unit of the air conditioner according to the first embodiment or the second embodiment is implemented by software. The processing circuitry 29 includes a processor 291, a random access memory 292, and a storage device 293. The processor 291 executes a program 29 b. The random access memory 292 is used as a work area by the processor 291. The program 29 b is stored in the storage device 293. The processor 291 deploys the program 29 b stored in the storage device 293 on the random access memory 292, and executes the program 29 b. As a result, the function of the control circuitry 19 is implemented. The software or firmware is described in a programming language, and stored in the storage device 293. The processor 291 can be exemplified by, but is not limited to, a central processing unit. It is possible to apply, to the storage device 293, a semiconductor memory such as a random access memory (RAM), a read only memory (ROM), a flash memory, an erasable programmable read only memory (EPROM), or an electrically erasable programmable read only memory (EEPROM) (registered trademark). The semiconductor memory may be a non-volatile memory or a volatile memory. Furthermore, in addition to the semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a Digital Versatile Disc (DVD) can be applied to the storage device 293. Note that the processor 291 may output data such as a calculation result to the storage device 293 to store the data in the storage device 293, or may store the data in an auxiliary storage device (not illustrated) via the random access memory 292.

The processing circuitry 29 implements the function of the control circuitry 19 by reading out and executing the program 29 b stored in the storage device 293. It can also be said that the program 29 b causes a computer to execute a procedure and method for implementing the function of the control circuitry 19.

Note that the processing circuitry 29 may be partially implemented by dedicated hardware and partially implemented by software or firmware.

Thus, the processing circuitry 29 can implement each of the above-described functions by means of hardware, software, firmware, or a combination thereof.

The configurations set forth in the above embodiments show examples of the subject matter of the present invention, and it is possible to combine the configurations with another technique that is publicly known, and is also possible to make omissions and changes to part of the configurations without departing from the gist of the present invention. 

1. An outdoor unit of an air conditioner, comprising: a refrigerant circuit including a compressor, a flow path switch, an outdoor heat exchanger, a decompressor, and indoor heat exchangers connected via refrigerant pipes; two outdoor fans to supply air to the outdoor heat exchanger, the two outdoor fans being arranged one above another; two fan motors to drive the respective two outdoor fans; a controller including two fan motor connectors and a fan motor power supply, the two fan motor connectors being capable of being connected to the fan motors, the fan motor power supply being capable of separately supplying power to each of the two fan motors connected to the fan motor connectors; and electrical component temperature sensors to measure temperatures of electrical components including at least components included in the controller, the electrical component temperature sensors being installed in an electrical component box in which the controller is enclosed, wherein the controller includes a control circuitry, wherein at a time of single-fan operation in which only upper one of the two outdoor fans is operated, the control circuitry is configured: to detect each of the two fan motors is connected to which of the two fan motor connectors; and to supply power in such a way to drive upper one of the outdoor fans based on a result of the detection, wherein the detection is performed based on comparison between temperatures of the electrical components at a start of the single-fan operation and temperatures of the electrical components after a set time has elapsed since the start of the single-fan operation.
 2. The outdoor unit of the air conditioner according to claim 1, further comprising: a connection state memory to store connection state information indicating each of the two fan motors is connected to which of the two fan motor connectors, wherein the control circuitry is configured: to read out the connection state information from the connection state memory at the start of the single-fan operation; and to determine the fan motor to be supplied with power through the fan motor power supply. 